Machine for testing clutch and brake assemblies



sept. 14, 1941s.`

MACHINE R. G. sTARLlNG 2,449,091

FOR TESTING CLUTCH AND BRAKE ASSEMBLIES Filed Jan. 2s, 1945 lll' Illllllllllllllllllllll IL l 0,- INVENTOR.

@fahnen 6. @r4/w. v6

Patented Sept. 14,v 1948 MACHINE FOR TESTING CLUTCH i Y BRAKE ASSEMBLIES Richard G. Starling, Harviell, Moi."

Application January 23, 1945, Serial No. 574,173 v imams. (c1. vs -.121)

(Granted under the act of March 3, 1883, as

The invention described herein may be manufactured and used by or forV the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a machine for testing clutch and brake assemblies, and more particularly for testing the plate and cork-disc assemblies of the clutch and the brake as used on servomotors of automatic pilots on airplanes.

In automatic pilots of airplanes, especially in the C-l pilots, electric servomotors are employed for actuation of the airplane controls, and the servo mechanism comprises a clutch which includes a plate and a cork-disc forming the two frictionally engaging elements for transmitting power from an electric motor to a cable drum, and when the electric motor is (ie-energized the clutch releases, and a brake which includes a plate and a cork-disc holds the cable adjusting mechanism in its adjusted position. In servicing the servo mechanism, a great deal of trouble hasv been encountered in obtaining the proper clutch and brake characteristics; that is, a clutch to transmit the proper torque and also to release promptly, and a brake to hold without slipping. In making repairs it has also been necessary to make repeated adjustments by tearing down and reassembling the units, and thus delaying the return to use of the airplane and alsol causing an excessive expenditure of time of the mechanics.

It is an essential object of this invention to provide a machine for testing the clutch elements and the brake elements while disassembled, so as to permit adjustment to be made and likewise defective clutch parts and brake parts to be found and replaced before they are installed; whereby the tested units may then, after any required adjustment and repair, be reassembled in the servo mechanism without any need for further adjustment', thus saving a great deal of time. Such testing mechanism is furthermore useful in the testing of the clutch and brake assemblies in the course of manufacture. Y

Another object of this invention is to` provide a clutch and brake testing machine which is capable of individual as well as joint and simultaneous testing of the associated clutch and brake assemblies of such airplane servo mechanism and the`like, and thereby shortening the testing operation and hastening return oi the airplane to use and also saving man-hours of work of the mechanics.

amended April 30, 1928; 370 0. G. 757) AVOther objects and advantages will more fully 5 appear from the following description taken in connection with the accompanying drawings wherein this invention is shown in its preferred form of construction.

In lthe drawings:

Fig. 1 is a plan view showing my invention in its operative position.

Fig. 2 is a longitudinal sectional view of the pair of chucks having the two .companion brake elements removably mounted therein.

Fig. 3 is a longitudinal sectional View of the pair of chucks having the two'companion clutch elements removably mounted therein.

Fig. 4 is anV enlarged longitudinal sectional view of the-pressure indicator used for the clutch assembly, and which construction is likewise used for the brake assembly.

In the form of construction illustrated in the accompanying drawings this invention comprises a base 'plate 5 supporting a sub-base or carrier member 6 sldable longitudinally thereon and held in place by latches 1 engaging side ridges on said base plate 5. Upon said carrier member 6 is mounted anv electric driving motor 3 which can be energized by manipulation of a control switch 9, and the motor armature shaft has a gear l0 mounted thereon, which drives a spur gear il mounted on a shaft I2 suitably journaled in bearings provided in vertical supporting plates I3 and i4 which are secured on said member G andare therewith slidable longitudinally outwardly on the base 5, to facilitate insertion and removal of the clutch and brake elements.

The means for holding the clutch elements'for the testing operation include a chuck I5 secured on :the inner end of shaft l2 to rotate with the shaft, and said chuck is Vprovided with spring means IB whose ends removably engage a retaining gear I1 faced with a washer-shaped corkdisc l8,said parts I1 and i8 together forming one part or element of the clutch assembly to be tested. A clutch plate i9, which forms a second part or element of the clutch assembly to be tested, is provided with rear pins 2i! wherewith itis removably secured in a cylindrical centering holder or chu-ck 2i, said chuck being provided withl external ratchet teeth 22 adapted to cooperate with a pivoted pawl 23 which permits the chuck 2l to rotate freely in one direction only. Said chuck 2l is mounted on the end of a shaft 24 which is suitably journaled in bearing plates 26, 2l and 28 secured to base plate 5.

The shaft 24 is axially movable as well as rotatable, and at its outer end it is seated in a pivot pocket' 32 formed in the intermediate part of a lever or arm `3i! which has its upper end pivoted at 3l to a lug 3| on the supporting plate 21. Through the lower end of said lever extends a rod 33 provided at its outer end with an adjustable thumb nut 34, which bears on the lever, and at its inner end with a head or abutment 35 which bears on a calibrated spring 36 housed in a tubular housing 31 mounted :ion fthe .plate 23 and slotted at its upper side to give a visual indication of the position of the head or abutment 35 relative to a scale 38 marked in pound units on the upper side of the .housing '531, Sas illustrated in Figs. 1 and 4. The arm for `lever 30 serves to apply a predetermined ,thrust -to shaft 24, as determined by the tensionloading applied to rod 33 by spring 36, Jtlreloa'dingaf 1 which is adjustable manually by thumbnut .34. The preset thrust on shaft 24 thus applies a predetermined pressure on clutch elements' I-'B and I which are to be tested.

The shaft 24 has azgear 40 rigidly mounted thereon and provided with -a .wide tooth .face so as to `remain in mesh witha.gear 4| which forms an input to a side gear f42aofla-diierential unit 45, said differential unit being-suitably supported from support 21-and has its opposite-side gear 43 mounted on a gear 461which=meshesfwith a wide faced :gear 41 whichis rigidly mounted Ton a shaft 48 journaled-for-freerotation andaxial movement `in bearings provided in :supporting members 26, :21,and28. Thershaft 48.i's adapted to be-adjustably loadedfinits axial-.idirectiom'by means of a-lever50 pivotedfat'l onfplate`2'l,and further means -and-manner-identical tothat of shaft`24 Lshown inYFig.--4. aid.lever.fhas azbearing pocket, like the-pocketsliZ`inflevers?ilpwherem 2'Y in the end of shaft 48 bea-rs rotatabli/.fland the lower end of said lever bears againstzan adjustable thumb` nut 54A secured to `the -vvendofz-atension rod 53 which extends throughaidflever and is provided with a headior abutment engaging a calibrated loading springsSEi-housedzinsa tubular housing 51 which is provided'witha loadingscal-e 53, similar to the scale.38 onfhousing--lfoff-Fig. 4. Adjustment of thumb nut y54 provides yazfmeans for applying any desired Apredetermined `raXi-al loading on shaft 4-8.

The shaft fili) is provided at itsinnerfend with a cylindrical chuck 6| `whiclfiz'iszadapted-togcenter and hold -an annular brakepressure;platef62, as by the use of Ipins 63, .forming -one part .of v.the brake elements to be tested; and it is adapted'to engage a washer-'shaped'cork-disc vf64 #carried :on the face of an yannularbacking-1.11am ".65 .which forms the second element vof 'the ybrake :to Nbe tested. The cork-disc :64 -fwith its backing :plate 65 is rmly butzremovably heldfinraastationary chuck 66 which is .secured onaarshaft 61 rigidly mounted on said plates I3 iand :114, said :shaft 161 being removable land likewise zslidable `longitudinally'with said plates'and sub-"base fzrelativezto .baser plate 5. The shaft 48-extends'throughl'the chuck-| and is oenteredandrotary'in anbearing .pocket 68 provided in ithezstationary .chuck 66, and said shaft 48 is thus;permittedotationalfand axial movement and insures fconceritricity :ibetween the brake elements whilebeing tested.

The carrier of the-'differential unit 4155is dri-vingly connected to 1an-output shaft 101-which-is journaled in asuitable bearingfasindicatedat 1I, and the shaft -hasfa cable drum 12 secured to its outerv end which-is'ofthe same diameter. as is the drum employed inthe servo mechanism for actuating the control cable. .A cable 73 iis secured at one end tosaididrum and'is .wrapped since the drum radius is constant for all servomotors, the reading in pounds on this scale of mymachine is all that is required for comparison purposes. The cable drum 12, cable 13 and spring balance ltogether form a dynamometer for ap- 'plying'loads of definite magnitude to the differ- :entialunit 45.

In making a test with this machine, the clutch and the brake assemblies are placed in the chuck -.units, l-Zl andfBI-BS, respectively, and the .brake :pressureiszadjusted by adjusting the axial loading on shaft 48 until it is certain that the brake-will notslip. The motora isthen. energized andfas the .torque-applied tothe drum 1.2 1increases, the readingon thescale 115.1ikewiseincreases until the clutch slips; .and .by-adjusting theV clutch loading pressure to` ar known .predetermined value, .lit can :be readily determined whether the .clutch 4will: or will not: slip within a known torque. range. and. hence whetherl the same will be satisfactory. Similarly, .ther clutch maybe adjusted by .increase .of pressure through l actua.- tionof adjusting.nut.34until.the clutch will not slip withinzaknown predetermined torqueirange, and thezbrakeloading can lthenbefadjusted*to/a predetermined --value `by .actuating .the `:adjusting nut .-54 .enabling Ya rapid determination :of :the slippingrpoint. or; limit .of the torque' applicable .to the ibrake. The characteristics `of :both units. while operating simultaneously, .may also Abe readily.- checked .by:adj.usting 'the-.clutch and the brake loadings by actuating thezr-espective adjusting nuts.34 and.54, .tolthedesiredpredetermined values, and -then energizing the driving motor `and determining 4whethenthe clutch -will transmit a desired .torque without slip and .-also whether the brake will hold -Withouteslip 'within that y'desired .range A`.By `thus v.rapidly `checking simultaneously both theclutch .and ythe brake assemblies, it -will be known whether -fsuch units are yserviceable -and Vactually what floadirig lis necessary to obtainthe desired results, and-thus there will be no need for repeated assembly-.and disassembly of the .servo mechanism to .obtain satisfactoryresults.

.Iclaimz ,1. A machine for :simultaneously :'testingfboth the clutch and -the'brake assemblies'of vthe type Whereineach--ofsaid assemblies. includesfa pairof elements `having yirictionalc engagement; said machine Acomprising two pairs of Y'holding members, one pai-rforlholding ythepOmpanion clutch elements Vand 'one pair .for :holding 1 the companion brake elements vin operative frictional engagement, fdifferential gearlneans operatively :connecting one of theclutchholdingmembersfwith one :of the lbrake holding members, means -'for driving von-e :of the tworemainin'g holding members and also means ffor holding "the Alastof'said holding members, 'a 'pair "of `individual loading pressure indie ators,l means y*op eratively4 connecting one th'ereof'witht'he clutch andthe other with the brake, a dynamometer and meansoperativly connecting'it with said member-.connecting :dif-

.ferentialgear .means .tobe-.actuatedthereby during .the operation :of .the .machine -to zindicate simultaneously the range of the torque loading of the combined clutch and brake assemblies.

2. A machine for simultaneously testing both the clutch and the brake assemblies of the type wherein each assembly includes a pair of elements having frictional engagement, said machine comprising two pairs of chucks, one pair for holding the companion clutch elements and the other pair for holding the companion brake elements in operative engagement, means operatively connecting one of the clutch chucks with on-e of the brake chucks, means for yrotating one of the two remaining chucks and also means for holding the last of the chwcks stationary during the testing operation, a pair of individual loading pressure indicators operatively connected with said chuck connecting means, one for the clutch and one for the brake, a differential unit interposed in said chuck connecting means and including a rotary member having secured thereon a cable drum, a spring balance and a cable connecting it with said drum and actuated by the operation of the machine and rotation of the drum to indicate the range of the torque loading of the combined clutch and brake assemblies.

3. A machine for simultaneously testing both the clutch and brake assemblies of the type used with servomotors of automatic pilots on airplanes and wherein each assembly comprises two companion elements including a plate and va corkfaced `member having frictional engagement, said machine comprising two pairs of chucks and a supporting shaft on each chuck, one pair of chucks for firmly holding the companion clutch elements and the other pair for firmly holding the companion brake elements, means for operatively connecting one of the clutch chuck shafts with one of the brake chuck shafts, a differential unit interposed in said connecting means and including a rotary member |carrying a drum to Iro- L tate therewith, means for rotatably driving the other of the clutch chucks and its shaft, means for holding the other of the brake chucks and its shaft stationary, a pair of pivoted levers, each for engaging and impeding :rotation of one of said two connected clutch and brake shafts, a pair of pressure indicators operatively connected with said levers, one for individually indicating the pressure loading applied to the clutch elements and the other for indicating the pressure loading applied to the brake elements, means for adjusting the pressure of said levers on said shafts, and a spring balance connected with said drum to be actuated by rotation thereof and arranged and constructed to indicate simultaneously the torque loading in pounds applied to the combined clutch and brake elements.

4. A machine for simultaneously testing both the clutch and brake assemblies of the type used with servomotors and wherein each assembly comprises two companion elements including a plate and a companion cork-faced member operable together by frictional engagement, said ma- |chine comprising two pairs of chucks, one pair for holding the companion clutch elements and the other pair for holding the companion brake elements, differential gear means for operatively connecting one of the clutch chucks with one of the brake chucks, means for rotatably driving the other of the clutch chucks, means for holding the other of the brake chucks stationary, a pair of pressure indicators, one being operatively connected with said one of the clutch chucks and the other with said one of the brake chucks, one for individually indicating the pressure applied to the clut-ch elements and the other for indicating the pressure applied to the brake elements, and a dynamometer operatively connected with said differential gear means connecting the two chucks and actuated by the operation of the rotatably driven chuck to indicate in pounds the torque loading on the combined clutch and brake assemblies.

RICHARD G. STARLING.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,490,603 Elverson Apr. 15, 1924 1,587,894 Bronk et al June 8, 1926 1,711,866 Williams May 7, 1929 1,890,219 Graham et al Dec. 6, 1932 2,050,887 Howarth Aug. 11, 1936 2,325,046 De Rentiis July 27, 1943 

